Linear Motor Core Shaft Cooling for Leak-Safe Miniaturization

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Solution Overview

Problem

The sealing performance of cooling water channels in linear motors is inadequate, leading to potential liquid leakage and compromising the safety and efficiency of the motor.

Innovation Solution

Integrating the cooling water channel and conductive component within the core shaft of the linear motor, eliminating the need for additional tubes, which enhances sealing performance, space utilization, and allows for compact, lightweight, and miniaturized design while improving heat dissipation through simultaneous cooling of both the conductive and winding components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate tube is arranged in the stator core shaft to form a cooling water channel, then the cooling function is achieved, but the sealing performance cannot be ensured and liquid leakage risk exists

Engineering Contradiction:
Improvesealing performanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cooling water channel with the core shaft by forming the channel directly within the shaft structure. The core shaft is designed with an integrated cooling water channel that runs through its interior, eliminating the need for separate tubes. This integration ensures better sealing performance as the channel becomes part of the shaft itself, reducing leakage risks while maintaining the cooling function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the separate tube component from the system and replaces it with an integrated channel design. By removing the need for additional sealing tubes and gaskets, the design simplifies the overall structure while improving reliability. The cooling water channel is directly formed in the core shaft, eliminating the interface between separate components that could potentially leak.

Inventive Principle:
Principle #2Taking out (Extraction)

2Temperature

If additional tubes are arranged for cooling, then cooling function is achieved, but the structure becomes more complex and weight increases

Engineering Contradiction:
Improveheat dissipationVSAvoidmotor weight
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The cooling water channel is merged with the core shaft structure, eliminating the need for separate cooling tubes. The channel is formed as an integral part of the shaft, reducing the total material required and thus decreasing the overall weight of the motor while maintaining effective heat dissipation from the conductive component and winding component.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If additional tubes are arranged for cooling, then cooling function is achieved, but the structure becomes more complex

Engineering Contradiction:
Improveheat dissipationVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling water channel is integrated directly into the core shaft structure, eliminating the need for separate cooling tubes and associated sealing components. This merger simplifies the overall structure by reducing the number of parts and assembly steps while ensuring effective cooling of both the conductive component and winding component through the unified channel design.

Inventive Principle:
Principle #5Merging (Combining)

4Temperature

If space is allocated for separate cooling tubes, then cooling is achieved, but space utilization is reduced and miniaturization is limited

Engineering Contradiction:
Improveheat dissipationVSAvoidmotor volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The cooling water channel is merged with the core shaft structure, allowing the cooling function to be achieved within the existing shaft volume without requiring additional space for separate tubes. This integration enables more efficient space utilization and supports miniaturization efforts by eliminating the need for extra cooling components that would increase the overall motor volume.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The integrated design ensures effective heat dissipation, prevents liquid leakage, and enhances the safety and efficiency of the linear motor by improving the isolation effect between the conductive component and coolant, while simplifying the motor's structure and components.

Implementation Method 1

the coolant can exchange heat with the conductive component and the winding component at the same time, thereby improving heat dissipation effects

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

A cooling water channel is arranged in the shaft wall... the coolant can exchange heat with the conductive component and the winding component

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4625767A1Linear motor, electromagnetic suspension, and vehicle
Publication Date: 2025.10.01 BYD CO LTD
  • EP4625767A1 patent drawingFigure 1
  • EP4625767A1 patent drawingFigure 2
  • EP4625767A1 patent drawingFigure 3

AI summary

The present disclosure discloses a linear motor, an electromagnetic suspension, and a vehicle. The linear motor includes: a primary assembly and a conductive component. The primary assembly includes a core shaft and a winding component sleeved outside the core shaft. The core shaft includes a shaft wall and a first chamber surrounded by the shaft wall. A cooling water channel is arranged in the shaft wall. The conductive component is arranged in the first chamber. The conductive component is electrically connected to the winding component and a motor controller respectively. In this way, the cooling water channel and the conductive component are both arranged in the core shaft, which is conducive to improving space utilization of the core shaft, and is conducive to achieving a miniaturized design of the linear motor. The cooling water channel is defined by the shaft wall of the core shaft, which improves integration of the core shaft. There is no need to arrange an additional tube. Moreover, the cooling water channel has good sealing performance, which can effectively avoid liquid leakage of the cooling water channel, and improve an isolation effect between the conductive component and a coolant. In addition, the coolant can exchange heat with the conductive component and the winding component at the same time, thereby improving heat dissipation effects of the conductive component and the winding component.